This is a great variation of the Northeast Ridge Route. It offers very enjoyable climbing (5.2 to 5.6) with some pretty intense exposure in a beautifully remote area of Rocky Mountain National Park. There is also a very unique part of this climb where you almost have to climb into a small cave and then up through a hole in the roof (having to take your backpack off to fit through it) which leads to 3rd class scrambling near the summit. This was a lot of fun!
See the "Getting There" section of the main page for basic directions for the approach to Hayden Spire.
In order to gain this ridge, there are a couple of ways to do it.
Via the Continental Divide
Traverse the 3rd class ridge from the divide until you get to the base of a large wall that blocks easy access to the summit spire. From here, drop down to you right (east) along some exposed ledges below the east face of the spire. It is fairly obvious which ledges will get you where you need to go. From here, you will be able to see the notch above you where you will need to go. You can climb directly up to it from these ledges via a 5.6 gully blocked by a chockstone, or you can wrap around to the other side of the ridge (again, the best line is fairly obvious), cross below a large steep slab and climb up a wide crack (4th+), that narrows as you climb. Use caution as a fall here would be leathal. The top of the crack meets the top of the gully from the other side at the notch.
Via Lonesome Lake
Climb a steep scree gully to the base of the ledge system mentioned above and continue to the notch from either side of the ridge. Or you can climb to the saddle between Hayden Spire and Hayden Lake Spire/East Pinnacle, and gain the notch from there via slabs and the large crack.
I will describe the route based on my experience. I went to the north side of the ridge and gained the notch by the large, narrowing crack. At the notch is where we roped up.
From here, you can break up the remainder of the climbing into 2 pitches (we did three because it was so windy that we couldn't hear each other very well and rope drag became an issue). I guess you could do it in one pitch, but rope drag would be horrendous. We never used half of my 60m rope for one pitch.
You begin from the notch by climbing up and through 2 small roofs (5.5/5.6). You can bypass the 2nd roof if you want to on 5.4 terrain to the right. You will then climb up through a small slot between rocks above you and to the right, to a large flat boulder.
From here, you will traverse around an airy corner, again to climbers right, and into a nice sized cave. Now look up! And climb through the hole (5.2ish) and up solid rock to the top of the ridge. To get through the hole you will most likely have to remove your pack, but there is a perfect ledge on climbers right, just inside the hole that seems to be made for a pack. From here it's 3rd class to the summit.
If you wanted to bring a bare minimum, you could get away with a set of nuts from #4 to #13. The largest cam we used was a Metolius #3 (smaller than a #1 camalot)...so I might bring at least cams up to a BD Camalot #1.
To be safe, go ahead and bring your full/standard RMNP rack. There are a lot of route variations and you could really use just about anything...
Prepare for a long day...plenty of water and food. You are above treeline for 99% of this hike, so prepare for that as well. There is no quick escape from bad weather either, so be well aware of what the sky is doing.
1st rappell from the summit.
To descend, you will just want to rappell off of the southeast side of the summit to a large ledge about 20 meters below. You will rappell just to skiiers left of a large overhang. Then you will set up another rappell to the south (in the direction of the divide) down a 20 meter wall to the ridge below. From there it is a short scramble back to the divide!
2nd rappell from top of the large wall on the south ridge